Cryogenic gas sampler



March 10, 1964 R. M. BROWN ETAL 3, 3, 8

CRYOGENIC GAS SAMPLER Filed Nov. 8, 1960 2 Sheets-Sheet 1 INVENTORS.Wl/AN/V 4 Me MAN/641 ll/brwey: fr I ixaa FIIIIII/l/IIlI/l/llll March 10,1964 R. M. BROWN ETAL 3,1 8

CRYOGENIC GAS SAMPLER Filed Nov. 8, 1960 2 Sheets-Sheet 2 Wi z A lBrown,

A/farneys fir AfflfCON/S United States Patent 3,123,982 CRYGGENIC GASSAMPLER Ross M. Brown and Robert C. Emmerling, Manhattan Beach, andAngel R. Florez, Downey, Calif., assignors to The Cosmodyne Corporation,Hawthorne, Calif., a

corporation of California Filed Nov. 8, 196i), Ser. No. 63,031 12Claims. (Cl. 62-55) Our invention relates to the art of taking samplesof liquefied gases such, for example, as nitrogen, oxygen, hydrogen,helium, and others, for analytic purposes; and relates more particularlyto a method and device whereby representative samples may be obtained.

As an illustration of the utility of our invention, the greatlyincreased use of cryogenic fluids for military purposes has created therequirement for control of the purity of these fluids. The principalproblem in obtaining satisfactory control has been the lack of asuitable method and device for obtaining and analyzing the fluidswithout significant alteration of the impurity level, or theintroduction of new impurities into the samples taken.

It is an object of our invention to provide a method and device in whichthe boiling off of any gas from the sample taken is substantiallyeliminated from the final sample in order that sample enrichment throughconcentration is minimized or completely eliminated.

It is another object of our invention to provide a method and devicewhereby a representative sample of liquefied gas may be obtained, inwhich the flow of fluid from the tank from which the sample is to betaken is employed to lower the temperature of the sampler receptacle andthat of the inlet valve and in which the fluid is thereafter flowed as aliquid gas into the sampler receptacle without boil-01f.

It is another object of our invention to provide the method andapparatus as set forth in the preceding paragraph and in which theinitial liquefiable gas used to cool the sampler receptacle is isolatedfrom the final liquid sample. This is important since the initialliquefied gas will have a concentration of impurities due to boil-offwhich occurs in the process of cooling the sampler receptacle becauseheat is necessarily absorbed by this precooling flow of fluid.

It is also an object of our invention to provide a meth- 0d and devicewhereby a representative sample of liquefied gas is obtained in liquidform and thereafter vaporized and stored as a gas within the samplerdevice.

It is a still further object of our invention to provide a method anddevice as referred to in the preceding paragraph in which, should anyboil-off occur in the sampler receptacle, this boil-ofl vapor will flowinto the gas storing chamber of the sampler device and will become apart of the sample taken and in this way the sample will be arepresentative sample without alteration of the impurity level.

Another object of our invention is to provide a sampler device forobtaining representative samples of liquefied gases in which the samplerreceptacle which receives the liquefied gas sample is positioned withinthe gasifying chamber into which the fluid will flow as a gas or liquidand will therein be stored as a gas for later analysis.

It is an object of our invention to provide a method and device of thecharacter referred to in the preceding paragraph in which the operationof obtaining the representative sample is a simple procedure involvingmerely the opening and the closing of a single valve.

It is also an object of our invention to provide a sampler as referredto in the preceding paragraph in which the device itself indicates whenthe sampler receptacle has been adequately cooled and the valve to thesampler receptacle should be opened; and also indicates 3,123,982Patented Mar. 1%, 1%64 when the sampler receptacle is full and when thevalve should be closed.

It is a further object of our invention to provide a sampler device asreferred to in the preceding paragraph in which the sampler receptacleis enclosed in a pressure vessel and in which the device is enclosed ina light weight separable cover, one part of which, when removed, makesan inlet operating valve accessible and the other part of which, whenremoved, makes a gas extraction valve accessible. Since the extractionvalve is operated by laboratory personnel only, it is desirable that itbe inaccessible When the sample is being taken.

It is a still further object of our invention to provide a liquefied gassampling device that is easy and safe to operate, durable, portable, andthat receives an unenriched and pure sample in suficient quantity to beadequate for testing.

Further objects and advantages of the invention may be brought out inthe following part of the specification wherein small details have beendescribed for the cornpetence of disclosure, without intending to limitthe scope of the invention which is set forth in the appended claims.

Referring to the accompanying drawings which are for illustrativepurposes only:

FIG. 1 is a side elevational view of a cryogenic gas sampler accordingto the invention, shown partially in cross-section, and including itsrectangular removably secured housing;

FIG. 2 is a fragmentary cross-sectional view taken as indicated upon theline 22 of FIG. 1;

FIG. 3 is a cross-sectional bottom View of the sampler device taken asindicated upon the line 33 of FIG. 1;

FIG. 4 is a fragmentary cross-sectional plan view taken as indicatedupon the line 44 of FIG. 1;

FIG. 5 is a fragmentary cross-sectional view taken upon the line 5-5 ofFIG. 1 and illustrating a closure on the cooling line and its reliefmeans; and

FIG. 6 is a fragmentary cross-sectional View taken upon the line 66 ofFIG. 1 and illustrating a surge pressure relief means adjacent theextraction valve.

Referring again to the drawings, there is illustrated in FIG. 1 apressure bottle 11 for retaining a vaporized gas sample, supported on abase frame 12 within a rectangular housing designated generally as 1.3.The housing 13 is comprised of a top section 14 forming a topcornpartment and a bottom section 17 forming a bottom compartment, thetwo compartments being separated by the base frame 12 which extendsbetween the pressure bottle and the outer walls of the compartments.Each of the compartments are removably secured to the frame member 12 attheir adjacent edges by peripherally spaced screws 18 and 19,respectively. The housing is provided with an unshown handle forcarrying and which may be attached to any of the outer walls of the topsection ltd.

A sampler receptacle generally designated as 20 is supported withinpressure bottle 11 and is comprised of a cup 23 forming a samplerchamber therein. The support means for the sampler receptacle include adisc shaped top 24, as shown in FIG. 4, and which in turn is supportedby a tubular member 25, having its lower end threadedly engaged in atapped opening 26 in the top 24 and having its upper end supported on amounting flange 2.9 which is scalingly secured in the top of bottle 11.

Surrounding the cup 23 is a cooling shield 30 forming a cooling jacket31 between the walls of the cup and the shield. The cup is sealed alongthe inner face of its Wall where it enters the top 24 by means ofbrazing ring 32 and the shield is similarly sealed externally by brazingring 35.

An inlet or fill means generally designated as 36 extends through amounting fixture 37 welded to the shell of bottle 11 and has on itsouter end a threaded fitting 38 for connection to a tank containing aliquefied gas from which a sample is to be taken. When the fitting 38 isnot so connected to take a sample, a closure 41 is threadedly engagedtherewith as shown in FIG. 1.

Extending inwardly from inlet 36 into the bottle 11 is a tube 42,, shownin FIGS. 1 and 4, threadedly and sealingly engaged in a passage 43 indisc 24. Inwardly of its threaded portion tube 42 extends through anopening 44 in the wall of shield 36 in which it is sealingly engaged andits inner end abuts the outer wall surface of cup 23 in a sealedrelationship, outwardly of opening 47 in the latter wall which is inalignment with passage 43.

Passage 43 provides the inlet for cup 23 and is sealed therefrom by asample obtaining valve 43 shown closed on seat 49. When valve 48 islifted off its seat passage 43 is connected to the cup by passage 50extending downwardly from the valve seat.

Passage 43 is also connected to an annular recess 53, provided to permitthe liquefied gas to cool the mass of the valve, and the annular recess53 is in turn connected to a passage 54, shown in FIGS. 2 and 4, whichconnects the inlet 36 to the cooling jacket 31.

Shown opposite the inlet in FIG. 1 is an outlet or drain generallydesignated as 55 having a fixture 56 sealingly welded in the shell ll.Extending outwardly of the fixture 56 is a threaded end portion 59 onwhich there is a closure 66 threacledly engaged, as shown, when thedevice is not connected to receive a sample. As best seen in FIGS. 1 and5, closure cap 66 has a threaded opening in its outer end in which isthreadedly engaged a flexible mushroomshaped plug 61 having its lips 62resiliently engaged on the outer surface of the cap. A passage 63through the center of plug 61 connects the outlet 56 with the undersurface of the lips 62 so that an excessive pressure within drain 55 isbled off through passage 63 and under lips 62.

Outlet fixture 56 is joined to the cooling jacket 31 by tube 64 whichhas its inner end threadedly engaged in top 24, the said end extendinginto an opening 65 in the wall of shield 30 in which it is sealinglyengaged.

The valve 48, which is hand operated to obtain a liquefied gas sample,has a stem 66, as shown in 'FIGS. 1 and 2, slidably and sealinglyengaged in support tube 25. Threadedly engaged in the outer end 69 ofthe stem is a spring holding pin 70 having a head 71 on its outer end.In abutment with the inner surface of head 71 and surrounding the pin isa washer 72 and spaced between washer 72 and the upper end 69 of thestem, surrounding the pin, is a valve adjusting coil spring '75.

The valve handle 76, which is exposed and accessible along with inlet 36and outlet 55 when the top section 14 v is removed, is fixedly threadedto the external threads of a nipple 77, which is in turn rotatablythreadedly engaged with the outer end 78 of tubular support member 25.In the outer end of the handle is a threaded central bore 79. Toposition the valve 43, after the handle is in closed position on tube25, the valve is inserted through the bore 79, into tube 25, and placedon its seat 49. A plug 86, having a central inwardly opening recess Si,is then threaded ly engaged in bore 79 to abut washer 72, the head 71extending into and being spaced from the inner surfaces of the recess81. With the handle 76 in the closed position, the plug it is tightenedagainst the force of the spring with a special wrench inserted intorecesses 32 in the top of the plug to pre-set the valve. That is, thevalve is pressure-tested and the plug and spring are adjusted until thevalve lifts at the desired pressure against the force of the spring,causing the head 71 to be moved off the washer and inwardly into recess81. When the handle is rotated for opening, along with its fixed nipple77 on threaded end 78, it is raised outwardly so as to raise plug 80 andpermit the washer to lift and the valve to be unseated.

As best seen in FIGS. '2 and 4, the cup 23 is vented to the pressurebottle ill by means of a passage 83 extending upwardly from the cup intothe top 24 and by means 4 of an extension of the passage in the form ofa vent tube 84 which is threadedly engaged in the top and extendsupwardly into the bottle. This venting means permits the gas samplecollected in the liquefied form to vaporize and expand into the gasbottle from which it is extracted to test the collected sample.

As best seen in FIGS. 1, 3, and 6, at the other end of the bottle 11 isa gas extraction valve housing designated generally as 86, separatedfrom the upper portions of the bottle by frame plate 12 when the twohousing members are as shown in FIG. 1 and being accessible when thelower housing member 17 is removed by withdrawal of the screws 19. Thevalve housing is connected to the bottle by means of a mounting nipple87 sealingly secured in the bottom of the bottle and by means of aT-fitting 83, which is threadedly engaged in the valve housing and at 90thereto, has a small diameter portion of the fitting 87 threadedlyengaged therein. Passage 89, as best seen in FIGS. 3 and 6, connects thebottle to passage 89a, the end of which forms valve seat 8% for valve91. The valve 91 is lifted off its seat by pressure in the bottle 11 orby a spring 91a, acting on stem disc 91!), when valve handle 9% isrotated to release the latter. When the valve is open, passage 89 isconnected through the valve to discharge outlet 92 which extends intothe extraction fitting 93 from which the gas is taken for testing. Whenthe device is not in operation the extraction fitting is sealinglyclosed by a threaded cap 94.

Threadedly engaged at the other end of the T-fitting 88 is a nipple 95having a passage 97 therein, connected at all times to passage 89 in thebottle. At the end of passage 97, as best seen in FIG. 6, there is ablowout disc 98, sealingly secured in position by plug 99 in an open endof the nipple 95. Safety disc is designed to burst at a predeterminedpressure which may be developed suddenly within the bottle 11 in theevent of excessive heating, for example.

In operation, to obtain a representative sample of a liquefied gas froma producing plant or a storage tank, the housing 13 is placed upright,as shown in FIG. 1, and the upper portion 14 is removed therefrom. Atthis time the valves 48 and 91 will have been closed in that the bottle11 and sampler cup 23 will have been evacuated either in manufacture orafter a previous extraction of a sample of gas through the valve 91.

The fitting 38 is connected to the tank from which a sample is to betaken after the closures 41 and 60 have been removed. A valve in theline connected to the fitting 38 is then opened so as to permit the flowof liquefied gas into the tubular passage 43 around the mass of thevalve 48, into the passage 54, as shown in FIG. 4, and then into thejacket 31 formed by the cup 23 and the shield 36. For a very short timethe liquefied gas entering the jacket 31 will tend to vaporize and flowout of the passage 64 in the outlet 55 but the cooling occurs so quicklythat the flow of vaporized gas may not be perceptible. In other Words,when the cup is cooled to a degree at which boil-off ceases, liquefiedgas will start to flow out of the outlet 55.

As a result of this cooling, no further vaporization or boiling off ofthe liquid will occur between the inlet 36 and the outlet 55'. This isan important feature of the invention because when boil-off occurs aliquefied gas becomes enriched with impurities as the impurities in thegas are less volatile than the pure gas. Thus, since there will be nofurther boil-off between the inlet and outlet on opposite sides of thebottle 11, a representative sample from the source externally of thebottle can be taken from the fiow path between the said inlet andoutlet. In other words, there will be no boil-off from the sample thatwill be allowed to flow into the cup 23 after the latter has beenproperly cooled. Further, the initial cooling gas, by virtue of theclosed valve 43, is isolated from the final liquid sample allowed toenter the cup and this is important, not only because of theconcentration of impurities in the boil-off in the initial gas, butbecause in addition, it may have acquired contaminants from the lineprior to reaching the sampler.

After the cooling has been accomplished and the jacket 31 and the tubes42 and 64 are filled with the flow of liquefied gas, the valve handle 76is rotated to open the valve 43 to permit the liquefied gas to flow intothe receptacle 23. Upon turning the handle 76 the lower surface of theplug 80 moves upwardly from the washer 72 so that the sealing force ofthe spring 75 is removed from the valve, and after further rotation, thenipple 77 in the handle makes positive contact with the lower surface ofthe washer to definitely cause the valve to be lifted off its seat. Theliquid then enters the receptacle through the short passage 54) directlybelow the valve seat and the flow of the liquid out of the tubes 64 ofthe outlet will tend to stop. However, as soon as the receptacle isfilled, and this occurs rapidly, the liquefied gas will again flowthrough passage 54, the upper portion of the jacket 31, and out of thepassage 64. Thus, when it is visibly observed that the liquefied gas isagain flowing out of the outlet 55 it is realized that the cup is filledand the valve can be closed. While the recurrence of the fiow out of theoutlet 55 is a positive indication that the receptacle 23 is filled,from experience it has been determined in one design of the invention,for example, that when the valve is rotated four turns to open it, bythe time the fourth turn has been completed the receptacle 23 is thenfilled and the valve may be immediately closed. Since the vent tube 84is open to the interior of the bottle 11 at a considerably higher levelthan the top of the jacket and the outlet, no liquefied gas will flowout of the top of the vent.

After the valve 48 is closed the valve of the tank from which a sampleis taken is then closed and the fittings removed from the inlet 38.Closures 41 and 60 are then threadedly engaged with the fittings 38 and59, respectively, and the housing top 14 is secured to the frame member12 by screws 18.

As the gas warms it will tend to vaporize and flow from the receptaclecup 23 out of the vent 84 into the bottle 11. In the event the pressurein the bottle and the cup increases to a predetermined amount greaterthan the force exerted by the spring 75, the valve will be lifted offits seat, forcing the pin head 71 upwardly in the recess 82, so as topermit fluid to flow through passage 56 into passage 54 and through theoutlet 55 into the passage 63 in the mushroom shaped plug 61. As long asthe pressure is just slightly greater than that of the downward force ofthe spring there will tend to be a leak through passage 63 and out underthe lips 62 of the plug. This, of course, occurs only during unusualcircumstances and this type of leak-off is provided only as a safetymeasure. Similarly, if there should be a sudden surge of pressuregreater than that required to blow out the safety blow out disc 98, thesaid disc will burst to reduce the pressure.

Generally, after a simple has been taken the housed device is shipped orcarried to a laboratory where the sample may be tested. To accomplishthe testing the housing portion 17 is removed by the withdrawal ofscrews 19 and extraction lines are connected to fitting 93 after cap 94has been removed. Valve 91 is then opened by the rotation of the handle9% and the sample of gas is permitted to be extracted from the bottleand the cup. As previously indicated, after the test sample has beenextracted the sampler receptacle 23 and the bottle 11 are evacuated soas to remove all possible contaminants for the next sampling operation.Thus, before the extraction line is removed from fitting 93, valve 91 isclosed and then the bottle and sampler receptacle are completely sealed.At this time the housing portion 17 is again secured to the frame member12.

From the foregoing, it is clear that other forms of the device andmethod disclosed herein may be used without departing from the principleof the present invention whereby a truly representative sample of aliquefied gas may be obtained for testing.

We claim:

1. In a cryogenic sampler: a sampler receptacle; a pressure vesselsurrounding said receptacle; an inlet to said receptacle extending fromthe exterior of said vessel and being controlled by a valve, said valvebeing operable from the exterior of said vessel; heat exchanger means onsaid receptacle connected to said inlet upstream of said valve; anoutlet from said heat exchanger means extending outwardly of saidvessel; and a vent from said receptacle to said vessel.

2. In a cryogenic sampler: a sampler receptacle; a pressure vesselsurrounding said receptacle; an inlet to said receptacle extending fromthe exterior of said vessel and being controlled by a valve, said valvebeing operable from the exterior of said vessel; heat exchanger means onsaid receptacle connected to said inlet upstream of said valve; anoutlet from said heat exchanger means extending outwardly of saidvessel; a vent from said receptacle to said vessel; and an extractionvalve for controlling a conduit to said vessel.

3. In a cryogenic sampler: a sampler receptacle having a valvecontrolled inlet; a pressure vessel surrounding said receptacle, saidinlet to said receptacle extending from the exterior of said vessel,said valve being operable from the exterior of said "essel; a coolingjacket surrounding a substantial portion of said receptacle connected tosaid inlet upstream of said inlet valve; an outlet from said coolingjacket extending outwardly of said vessel; a vent from said receptacleto said vessel; an extraction valve externally of said vessel forcontrolling a conduit extending therefrom; and a cover for said pressurevessel comprising two parts, said parts being separately attachable andremovable from said vessel, one of said parts enclosing said inlet valveand said inlet and outlet, the other of said parts enclosing saidextraction valve.

4. A method of obtaining a representative sample of a liquifiable gasfrom a tank comprising: flowing a liquefied gas, from a tank from whicha sample is to be taken, adjacent to and isolated from a samplerreceptacle to lower the temperature of the receptacle to a degree tominimize boil-off; flowing said liquefied gas from adjacent saidreceptacle to the atmosphere to indicate when the temperature of thereceptacle has been lowered to the degree at which boil-off isminimized; and thereafter continuing said flow of said liquefied gascausing said gas to flow into said receptacle.

5. A method of obtaining a representative sample of a liquefiable gasfrom a tank comprising: flowing a liquefied gas, from a tank from whicha sample is to be taken, adjacent to and isolated from a samplerreceptacle to lower the temperature of the receptacle to a degree tominimize boil-off; thereafter causing said gas in liquefied form to flowinto said receptacle; and flowing said sample from said receptacle intoa gasifying chamber.

6. The method of obtaining a representative sample of a liquefiable gasfrom a tank comprising: flowing a liquefied gas, from a tank from whicha sample is to be taken, adjacent to and isolated from a samplerreceptacle to lower the temperature of the receptacle to approximatelythat of said gas until the fluid flowing from the adjacency of saidsampler receptacle is in liquid form; and thereafter continuing saidflow of said liquified gas causing said gas in liquefied form to flowinto said receptacle.

7. The method of obtaining a representative sample of a liquefiable gasfrom a tank comprising: flowing liquefied gas, from a tank from which asample is to be taken, adjacent a sampler receptacle to lower thetemperature of the receptacle until the fluid flowing from the adjacencyof said receptacle is in liquid form; continuing said flow of saidliquefied gas causing said gas in liquefied form to flow into saidreceptacle; and isolating said sample of liquefied gas in said samplerreceptacle.

8. The method of obtaining a representative sample of a liqueflable gasfrom a tank comprising: flowing liquefied gas, from a tank from which asample is to be taken, adjacent a sample receptacle to lower thetemperature of the receptacle until the fluid flowing from the adjacencyof said receptacle is in liquid form; causing said gas in liquefied formto flow into said receptacle; isolating said sample of liquefied gas insaid sampler receptacle; and flowing said sample directly into agasifying chamber.

9. In a cryogenic sampler: a sampler receptacle; a gas inlet to saidreceptacle controlled by a valve; and heat exchanger means on saidreceptacle connected to said inlet upstream of said valve, said heatexchanger means being in communication with said receptacle when saidvalve is open.

10. In a cryogenic sampler: a sampler receptacle; a gas inlet to saidreceptacle controlled by a valve; first heat exchanger means on saidreceptacle being in communication with said receptacle when said valveis open; and second heat exchanger means in communication with saidfirst heat exchanger means to cool the mass of said valve controllingsaid inlet.

11. In a cryogenic sampler: a sampler receptacle; a gas inlet to saidreceptacle controlled by a valve; heat exchanger means on saidreceptacle; and a common gas supply line to said receptacle inlet and toan inlet to said heat exchanger means, said heat exchanger means beingin communication with said receptacle when said valve is open.

12. In a cryogenic sampler: a sampler receptacle; a pressure vesseladjacent said receptacle; an inlet to said receptacle being controlledby a valve; heat exchanger means on said receptacle connected to saidinlet upstream of said valve; an outlet from said heat exchanger means;and vent means from said receptacle to said vessel.

References Cited in the file of this patent UNITED STATES PATENTS1,998,629 Lagarde Apr. 23, 1935 2,882,694 Vander Arend et a1. Apr. 21,1959 2,966,040 Henry cc. 27, 1960 2,976,695 Meade Mar. 28, 1961 FOREIGNPATENTS 728,134 Germany NOV. 20, 1942 OTHER REFERENCES

6. THE METHOD OF OBTAINING A REPRESENTATIVE SAMPLE OF A LIQUEFIED GASFROM A TANK COMPRISING: FLOWING A LIQUEFIED GAS, FROM A TANK FROM WHICHA SAMPLE IS TO BE TAKEN, ADJACENT TO AND ISOLATED FROM A SAMPLERRECEPTACLE TO LOWER THE TEMPERATURE OF THE RECEPTACLE TO APPROXIMATELYTHAT OF SAID GAS UNTIL THE FLUID FLOWING FROM THE ADJACENCY OF SAIDSAMPLER RECEPTACLE IS IN LIQUID FORM;